Use BoringSSL in the implementation of ClearKey for Chromecast.

Use BoringSSL in the implementation of ClearKey for Chromecast.
(Previously, this was used only with the "Chrome" branding).

BUG=488572
R=gunsch@chromium.org

Committed: https://crrev.com/defd2af08f3753687cb2d86b34bbec9da31ccbab
Cr-Commit-Position: refs/heads/master@{#330156}

[gunsch, 2015-05-15 18:07:50]

lgtm

[ddorwin, 2015-05-15 18:09:22]

ddorwin@chromium.org changed reviewers:
+ ddorwin@chromium.org

[ddorwin, 2015-05-15 18:09:22]

Drive-by commit message nit: Wasn't this only used with branding != "Chrome"
before?

[gunsch, 2015-05-15 18:11:04]

The internal one was linking in openssl in some situations, and used to be to
shim across older versions of Chromium (when we didn't have boringssl in our
downstream fork). No longer an issue.

[dougsteed, 2015-05-15 18:47:34]

The CQ bit was checked by dougsteed@chromium.org

[commit-bot: I haz the power, 2015-05-15 18:50:22]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1130893008/1

[commit-bot: I haz the power, 2015-05-15 19:07:37]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-15 19:09:33]

Patchset 1 (id:??) landed as
https://crrev.com/defd2af08f3753687cb2d86b34bbec9da31ccbab
Cr-Commit-Position: refs/heads/master@{#330156}

[gunsch, 2015-05-15 23:22:38]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1141243003/ by gunsch@chromium.org.

The reason for reverting is: Temporary revert until Monday (blocked on some
other internal changes)..